1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for acquiring a resource for an uplink control channel in a wireless communication system.
2. Related Art
The next-generation multimedia wireless communication systems which are recently being actively researched are required to process and transmit various pieces of information, such as video and wireless data as well as the initial voice-centered services. The 4th generation wireless communication systems which are now being developed subsequently to the 3rd generation wireless communication systems are aiming at supporting high-speed data service of downlink 1 Gbps (Gigabits per second) and uplink 500 Mbps (Megabits per second). The object of the wireless communication system is to establish reliable communications between a number of users irrespective of their positions and mobility. However, a wireless channel has abnormal characteristics, such as path loss, noise, a fading phenomenon due to multi-path, inter-symbol interference (ISI), and the Doppler Effect resulting from the mobility of a user equipment. A variety of techniques are being developed in order to overcome the abnormal characteristics of the wireless channel and to increase the reliability of wireless communication.
A cellular network based wireless communication system includes a homogeneous network or a heterogeneous network and interferences may occur among homogeneous base stations in the homogeneous network and among heterogeneous base stations in the heterogeneous network. Interference by other base stations may influence even a control channel as well as a data channel. Downlink control channels including a physical downlink control channel (PDCCH), a physical control format indicator channel (PCFICH), a physical HARQ indicator channel (PHICH), etc, may be transmitted in all subframes and may be allocated to an entire downlink bandwidth to be transmitted, and as a result, it is difficult to avoid the interference by other base station rather than the data channel.
In order to reduce the influence of the interference, introduction of a new control channel is discussed in addition to a current PDCCH. The new introduced control channel may be an enhanced PDCCH (e-PDCCH). The e-PDCCH may be defined to reduce the influence of the interference or introduce a new transmission mode. For example, the e-PDCCH may be defined to effectively support coordinated multi-point (CoMP) transmission.
Meanwhile, an acknowledgement (ACK)/non-acknowledgement (NACK) signal which is a response to downlink transmission may be transmitted through a physical uplink control channel (PUCCH) resource determined based on the PDCCH. With the introduction of the e-PDCCH which is the new control channel, the PUCCH resource needs to be acquired based on the e-PDCCH.